A Phase 1 Study to Investigate the Safety and Pharmacokinetics of Fosigotifator in Patients With Amyotrophic Lateral Sclerosis

Inclusion Criteria: * Must have an identified, reliable caregiver. * Confirmed diagnosis of Familial Amyotrophic Lateral Sclerosis (ALS) or Sporadic ALS. * First ALS symptoms occurred \<= 36 months before screening. * Able to swallow solids. * No known active COVID-19 infection at screening. * Slow vital capacity (SVC) \>= 50% predicted value (for sex, age, ethnic origin, and height) at screening. * If taking concomitant standard-of-care medications approved for the treatment of ALS (or their components), subjects must be on a stable dose of the medication(s) for \>30 days prior to Baseline in order to enter the study. For edaravone, a stable dose is defined by having completed 2 treatment cycles prior to Baseline. Exclusion Criteria: * History of dementia/severe cognitive problems at screening. * History of clinically significant medical conditions (other than ALS) or any other reason, including any physical, psychological, or psychiatric condition that, in the opinion of the Investigator, would compromise the safety or interfere with the subject's participation in the study, or would make the subject an unsuitable candidate to receive study drug, or would put the subject at risk by participating in the study. * History of abnormal screening laboratory or imaging results that, in the opinion of the Investigator, are indicative of any significant cardiac, endocrinologic, hematologic, hepatic, immunologic, infectious, metabolic, urologic, pulmonary, gastrointestinal, dermatologic, psychiatric, renal, neurologic, and/or other major disease that would preclude administration of Fosigotifator. * Documented active or suspected malignancy or history of any malignancy within the last 5 years except for successfully treated non-melanoma skin cancer or localized carcinoma in situ of the cervix. * If female, is known to be pregnant, breastfeeding, considering becoming pregnant, or donating/banking eggs during the study or within 30 days or \>5 half-lives (whichever is longer) after the last dose of study drug. * If male, plans to donate sperm or father a child during the study or within 30 days after the last dose of study drug. * Known to have received any investigational product within 30 days or 5 half-lives of the drug (whichever is longer) prior to the first dose of study drug or is currently enrolled in another clinical study. * History of Fosigotifator use prior to participation in this study. * Recent (within 6 months prior to Screening) history of drug or alcohol abuse. * Previous participation in a stem cell clinical study for treatment of ALS. * Current or anticipated use of diaphragmatic pacing during the study period. * Tracheostomy or use of non-invasive ventilatory support \>= 22 hours a day.